Glomerulonephritis (GN), an important human disease thought to result from immune complexes (IC) formed or deposited in glomeruli, is associated with significant morbidity and hemodialysis expense. Currently, therapy is limited in both efficacy and options. It is hypothesized that diminishing the glomerular content of the inciting IC should be beneficial and could break a vicious cycle in which immune injury enhances IC deposition resulting in more damage. Applicant's recent publications and other preliminary data show that proteolytic enzymes given systemically to mice and rats do reduce IC deposited in glomeruli and can prevent and reverse proteinuria in acute animal models of GN, and that targeting therapeutic enzymes to the sites where IC lodge improves efficacy. He now seeks to focus on the effects of enzyme therapy on the long term course of experimental GN. He will maintain rats with a model of GN for up to two years with periodic antigen re-challenge to keep the rats nephrotic, and study two distinct mouse models which also progress to sclerosis. Enzyme-treated rats or mice will be compared to controls to determine if treatment can prevent or diminish progression to end stage kidney. Glomerular filtration rate and glomerular scarring will be the criteria to assess progression, and will be compared by multivariate nonparametric analysis. He will examine chronic toxicity by light and gross morphologic examination of tissues, and by measuring release of intracellular enzymes into the plasma. He will also assess renal, liver and lung function by measuring urine concentrating ability, bile concentration in serum, stool fat content and oxygen and carbon dioxide tension in arterial blood. A second goal is to determine the extent to which active enzymes, as opposed to inactive enzymes, digest immune complexes deposited in the kidneys versus those in the circulation, and attempt to elucidate if any other mechanisms exist whereby proteases ameliorate GN. A third set of experiments will measure selected mediators of inflammation, known to be increased in a model immune complex glomerulonephritis to be studied, and determine if the production of these mediators, in the chronic phase, is influenced by enzyme therapy. In addition, he will correlate production of each mediator with glomerulosclerosis and glomerular filtration rate, to determine if any of the mediators is likely associated with progressive glomerular injury. The fourth goal is to extend the principle of enzymatic hydrolyis of immune complexes to a model of glomerulonephritis with nucleic acids implicated as antigens.